Resistance element



THEODORE W. GASE, OF SCIPIG, 'NEW YORK.

RESISTANCE ELEMENT.

masses.

31o Drawing.

T 0 all whom it may concern:

Be it known that I, THEODORE V. CASE, of Scipio, in the county ofCayuga, in the State of New York, have invented new and usefulimprovements in Resistance Elements, of which the following, taken inconnection with the accompanying drawings, is a full, clear, and exactdescription.

This invention relates to a certain new and useful variable resistance,and more specifically to to a resistance element of that class,characterized by the fact that the resistance of the element to thepassage of an electric current therethrough varies with variations inintensity of the light rays to which the element is exposed.

The invention contemplates the production of a light sensitive elementadapted to constitute a portion of an electric circuit, subject to thecondition that variations in intensity of the light rays to which theele ment is exposed produce a corresponding variation in the electricalresistance of the element, thereby effecting a variation of electriccurrent in the circuit in accordance with variations of light intensityto which the element is exposed.

I have discovered that a resistance element comprising or consisting ofa compound of thallium and bromin can be utilized as a portion of anelectric circuit, and that its resistance to the passage of electriccurrent through said circuit varies under the infiuence of light toeffect a change of current inversely in accordance with the intensity oflight rays to which the substance is sub jected. Further, thalliumbromld 1s peculiarly etlicient for this purpose, and highly sensitive tovariations of light intensity, due to the fact that the ratio of changeor percentage change of its resistance to the passage of anelectriccurrent under variations of light intensity is great.

The material, compound or resistance ele- Specification of LettersPatent.

Application filed March 15, 1920.

lfia'ten'te d June 8, 192%.

Serial No. 365,898.

ment may be incorporated in an electric cir cult in any suitable way,and said element may constitute any portion or part of such circuit, andwhen so incorporated the element may be supported in any suitable wayfor contact and exposure to light rays. i

The invention is adapted for and may be applied to various uses, as. forinstance. in the Bell photophone, or the apparatus of my co-pendingapplication, Serial No. 213,225, and I therefore desire to broadly claimthe same without restriction as to the method, manner or condition ofuse, and without limitation as to the addition of any other element orelements to thematerial or compound so long as the same do not destroythe utility of the material for the purpose described, and I desire toclaim the material for use with either direct, pulsating direct, oralternating current.

The expression light rays as used in the specification and claimshereof, is deemed to include all usable rays throughout the spectrum.

lVh-at I claim is l. A resistance element formed of a compound ofthallium and bromin.

2. A resistance element formed of a compound comprising thallium andbromin.

3. A resistance element formed of a material comprising a compound ofthallium and bromin.

l. An electric circuit having a portion supported for exposure to lightrays, such portion comprising a compound of thallium and bromin.

In witness whereof I have hereunto set my hand this 10th day of March,1920.

THEODORE TV. CASE.

Witnesses:

EARL I. SPONABLE, MAY F. GLEASON.

